I have a 99 civic LX with only 98,000 miles on it. Recently I just noticed that the front windshield deforst when turned on barely blows or not at all sometimes. Is this due to a cabil air filter issues or is there someting electronically wrong? Sometimes it acts like nothing is wrong (for the most part) but I don't think it blows as well as it used to.

 

Does the fan motor still sound like it's running strong? Does plenty of air come out of the dash vents when you select those instead of defrost?

 

The fan motor sounds as good as the day I bought it, and when the other settings are on, it blows just fine. It doesn't sound like it's stressing or anything. Only when that defrost is on, it seems to blow weak.